Demi-Hollow : This is an earthbound spirit that is decending into being a Hollow. This process usually takes more than a month to complete, unless it is forced by opening the hole located in the spirits chest.

Earthbound spirits : These are ghosts that wander a specific territory of land that had some importance to them in their life. Since they are assimilated with the ground they haunt, Soul Society devices rarely pick up on them.

hollows : Spirits that are evil. There are several ways one can become a hollow. If you die and are damned to walk the ground that you died or somewhere that is important to you, over time the hole where your heart was will grow and you will eventually be turned into a hollow (the hole can be forcefully opened and turn you into a hollow instantly as well). You can also become a hollow by being eaten by a hollow. Once you are a hollow - you first seek out the souls of loved ones in your human life. This is to help ease the pain and suffering. After that, you begin toseek out to eat souls of high spiritual concentration. The main way to defeat a hollow is by cutting off it's head.

Menos : This is a gigantic hollow formed by many small hollows combining.

Modified Soul : These are artificial spirits that were created to be inserted into dead humans, thus giving them a body and use it to fight off hollows. These mod-souls are gifted with strength that no normal human would be able to have.

Pluses : These are the good spirits! These spirits are ghosts that die but do not become hollows, and are not very harmful to anyone. These pluses are sent to soul society by the shinigami - where they can eternally rest.

Target leeches : These are leeches spit out by ghosts that are able to explode with a mere thought of the ghost

the swords that they carry; their zanpaku-to. the blades of Bleach are characters in and of themselves, with quirks and personalities of their own.

A zanpaku-to is the direct reflection of the power of its wielder, a shinigami's spiritual pressure given physical form. While they mostly look like any other katana an old-time samurai might carry around, zanpaku-to are far from normal. The foremost difference is the ability of zanpaku-to to harm shinigami. Since shinigami are really a kind of ghost, normal blades and weapons can't touch them. In fact, "zanpaku-to" literally means "soul cutting sword."

The other major point that separates them from plain old' swords is a zanpaku-to's ability to transform. Each blade has up to three distinct forms which its wielder can acces according to their strength and skill. The first, and one that doesn't take any effort to attain, is the blade's normal form. With a few exceptions, a zanpaku-to's normal form is indistinguishable from that of a plain katana.

The second form is called "Shikai", or "first release". The key to Shikai is learning the zanpaku-to's name. Discovering it is not the easiest thing in the world; some Shinigami never do manage it. But for those that do, they gain a whole new level of power. Easily triggered by an incantation unique to each sword, a shikai zanpaku-to changes immensely, often becoming a weapon far removed from a sword. Also, shikai zanpaku-to usually have special powers a shinigami can use, such as poisons, illusions or power blasts.

"Bankai", the third form, means "all release". Only shinigami at the Captain's rank, or highly powerful Vice-Captains can acquire bankai. Increasing the zanpaku-to's power by as much as a factor of ten, it takes many decades of intense training to learn bankai (or three days of cheating courtesy of Urahara and Yoruichi. ^^) Triggering a zanpaku-to's bankai needs only a one-word incantation: Bankai.

Bankai zanpaku-to get additions to their names, indicating it is New and Special, and it changes even more drastically, usually (presently with only 1 exception) becoming something far, far larger than the wielder.

26 zanpaku-to have been introduced, and we've seen 7 Bankai. But there are still several Captains and Vice-Captains who haven't shown us what their zanpaku-to can do, and several of the blades we have seen have only given us teasers. So this list is not nearly finished yet